The Gemini space program was originally seen as a simple extension of project Mercury. It was designed to develop techniques for more advanced space travel, paving the way to Project Apollo and its objective of landing a man on the moon.

The main objectives of the Gemini program were to observe the effects of long duration space flights on astronauts, to establish rendezvous and docking techniques between vehicles, and to perfect the method of landing spacecraft at a pre-selected point. The project was announced in December 1961 and ran until 1966. The total cost was $5.4 billion.

The word Gemini means 'twins' in Latin and each of the Gemini spacecraft were designed to carry two astronauts. As a result the Gemini spacecraft were larger than those that had been used in Project Mercury. The earlier Mercury capsules had been very small. They were filled with a huge number of switches, fuses and levers, meaning they were only just large enough to carry a single crewman. The Gemini capsules, on the other hand, managed to free up some space by placing many systems, such as life-support, in a separate section of the craft. The Gemini spacecraft were also designed to be able to change their own orbit meaning that they would be able to carry out rendezvous and docking procedures with other vehicles. To help them with this the spacecraft had their own onboard computer.

The astronauts for Gemini were made up of veterans from the Mercury program and 13 new recruits. The selection of crews was the responsibility of Deke Slayton who gave the original Mercury astronauts the first choice of missions. However, the crews were often re-arranged by Slayton to ensure the best combination of astronauts and each mission now had both a primary and a backup crew.


Ed White during his spacewalk (NASA)

The Gemini project was a great success and led to many important milestones in America's space program. For example, on June 03rd 1965, Ed White became the first American to carry out a space walk. White spent over 15 minutes performing manoeuvrability experiments outside Gemini 4, using a nitrogen powered gun.

This Extra-vehicular activity (EVA) had not actually been planned as part of the original mission. However, when Aleksei Leonov became the first man to carry out an EVA in March 1965, the Americans were keen to show that they were not falling further behind the Soviets. By the final Gemini mission, Gemini 12, NASA had proved that space walks could be carried out both easily and efficiently, with Buzz Aldrin performing three EVA's over the course of three days.

Gemini did encounter a few problems, however, such as those experienced by David Scott and Neil Armstrong on Gemini 8. The astronauts had to abandon the mission just 10 hours into their flight when the spacecraft began to roll at a rate of one revolution per second. This problem was caused when one of the spacecraft's thrusters became stuck, but Armstrong was able to stop the spinning by using the capsule's reentry control thrusters and performing the first emergency landing of a manned U.S. spacecraft. Despite the disappointment of the mission, it had shown that Armstrong was able to maintain a cool head during emergency situations and this proved critical in his later selection for Apollo 11.